Why is a 1 solar-mass red giant more luminous than a 1 solar-mass main-sequence star?
A) The red giant has a hotter core.
B) The red giant's surface is hotter.
C) The red giant is more massive.
D) Fusion reactions are producing energy at a greater rate in the red giant.
D
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The Moon is in the habitable zone of the Sun at the same distance as the Earth but is not habitable. How can this be?
A) the Moon did have water on its surface in the past, but it was destroyed by high-energy particles from the Sun B) the Moon has never had water on its surface at any time C) the Moon is too small to retain an atmosphere necessary for liquid water to be stable D) the Moon did have water on its surface in the past, but it was blasted off the surface by impacts
A pilot makes an outside vertical loop of radius 320 m. At the top of his loop he is pushing down on his seat with only one-half of his normal weight. How fast is he moving?
What will be an ideal response?
How does density divide the stars in the H-R diagram into three groups?
What will be an ideal response?
As we look at larger and larger scales in the universe, we find:
A) smaller and smaller masses. B) almost exclusively visible matter. C) a larger and larger percentage of the matter is visible. D) a larger and larger percentage of the matter is dark. E) an equal amount of visible and dark matter.